Zou Minmin, Liu Qing, Wu Chao-Feng, Wei Tian-Ran, Tan Qing, Li Jing-Feng, Chen Fei
School of Materials Science and Engineering, Beijing Institute of Petrochemical Technology Beijing 102617 China
College of Materials Science and Engineering, Beijing University of Chemical Technology Beijing 100029 China.
RSC Adv. 2018 Feb 13;8(13):7055-7061. doi: 10.1039/c7ra12819c. eCollection 2018 Feb 9.
AgBiSe and AgSbSe, two typical examples of Te-free I-V-VI chalcogenides, are drawing much attention due to their promising thermoelectric performance. Both compounds were synthesized melting and consolidated by spark plasma sintering. The role of annealing on the transport properties of polymorphous AgBiSe and monophase AgSbSe was studied. Annealing has a greater impact on AgBiSe than AgSbSe, which is ascribed to the temperature dependent phase transition of AgBiSe. Unannealed AgBiSe shows p-n switching, but annealed AgBiSe exhibits n-type semiconducting behavior over the whole measurement temperature range. By performing high-temperature Hall measurements, we attribute this intriguing variation to the change in the amount of Ag vacancies and mid-temperature rhombohedral phase after annealing. Both AgBiSe and AgSbSe exhibit low thermal conductivity values, which are ∼0.40-0.50 W m K for AgSbSe and ∼0.45-0.70 W m K for AgBiSe, respectively. The maximum value of AgBiSe is enhanced from 0.18 to 0.21 after annealing. Pristine AgSbSe presents a value as high as 0.60 at 623 K, although slight deterioration emerges after annealing.
AgBiSe和AgSbSe是无碲I-V-VI族硫族化合物的两个典型例子，因其具有良好的热电性能而备受关注。这两种化合物均通过火花等离子体烧结进行熔化和固结合成。研究了退火对多晶型AgBiSe和单相AgSbSe输运性质的影响。退火对AgBiSe的影响比对AgSbSe的影响更大，这归因于AgBiSe的温度依赖性相变。未退火的AgBiSe表现出p-n转换，但退火后的AgBiSe在整个测量温度范围内均表现出n型半导体行为。通过进行高温霍尔测量，我们将这种有趣的变化归因于退火后Ag空位数量和中温菱面体相的变化。AgBiSe和AgSbSe均表现出较低的热导率值，AgSbSe的热导率约为0.40-0.50 W m K，AgBiSe的热导率约为0.45-0.70 W m K。退火后，AgBiSe的最大值从0.18提高到0.21。原始的AgSbSe在623 K时呈现高达0.60的值，尽管退火后略有下降。
